This invention generally pertains to aircraft wheels and more particularly to a wheel drive key and heatshield assembly applicable to aircraft multi-disk wheels and brakes.
Many presently designed forged aluminum wheels which are used on large jetliner aircraft are characterized by channel-type drive keys oriented in a manner to engage rotor disks of a multi-disk brake, alternately mounted disks of the brake being relatively stationary and keyed to a brake torque tube-member. The wheel drive keys are U-shaped channels which may be as long as a foot in length and these are mounted on axially-oriented key bosses machined into and forming an integral part of an inboard-facing bore surface of the wheel. The channel keys are affixed and maintained in place on the key boss by screws which thread into bores in the boss.
Forged aluminum aircraft wheels, while offering lighter weight, are costly to manufacture because of the critical tolerances and heat treatment processing required. The wheel drive keys, which are manufactured apart from the wheel, are subject to various misalignments when being mounted on the key bosses and such misalignments may result in stresses being placed on the drive key, the key boss, and/or the mounting screws. Such stresses may also be increased during actual operation by thermal differential expansion forces between the various metals which comprise the parts and this results in premature fatigue cracking in the overstressed areas. This, of course, is detrimental to the continued safe operation of the total wheel and brake assembly.
It is, therefore, in accordance with one aspect of the present invention, an object to provide a drive key and heatshield assembly applicable to aircraft wheels which reduces the occurrence of stress fracturing while being lighter in weight and more economical to manufacture than presently configured wheel drive key assemblies.
In accordance with another aspect of the present invention, it is an object to provide a drive key and heatshield assembly that is structurally superior and eliminates many of the field servicing problems which have plagued other configurations proposed for the same service and application. SUMMARY OF THE INVENTION
A drive key and heatshield assembly adapted for mounting in association with a plurality of longitudinal and axially-oriented wheel key bosses which are integrally formed on an inboard-facing bore surface of a forged wheel comprises in combination:
a plurality of rectangularly-shaped drive key wearplates, the wearplates mounted in pairs on each of said wheel key bosses and each wearplate characterized by at least two longitudinal slots within the top and bottom edges of the wearplate; PA1 retaining means mounted transversely across the top surface of each wheel key boss and having sufficient length to engage each of the pair of mounted drive key wearplates within the slots on the top edges of the wearplates; and PA1 a plurality of substantially rectangularly-shaped heatshields each having a curved configuration which substantially matches the curvature of the wheel bore and positioned between adjacent wheel key bosses within the bore and characterized by at least two tabs extending from opposite lateral edges to engage the slots in the bottom edges of respective mounted drive key wearplates, said heatshields being substantially restrained from both axial and radial movement within the wheel bore.